It makes a difference whether you always force a bell curve that way, or whether you have a fixed set of standards in which any student, in principle, could excel without hurting the others.
I went back to school for some courses in a new area, and half the students were, er, “entitled”. They clearly were in way over their heads, but it was a city subsidized university. They had to be there, and they had to pass. I asked the professor how he handled the grading curve. He said that with a curve this bimodal, he simply separated the to ‘bells’, and super-imposed them. The grade for the average from the top bell was a B-, and the grade for the average from the low bell curve was a B-. He said that the, er, “entitled” students always dropped out anyway, so inflating their grades did no harm. And this way he didn’t get a knife in his ribs in the parking lot.
I have fixed standards and they are laid out in each course syllabus. Of course most students can’t be bothered to read the syllabus. I did love the Journalism major last semester that complained to me about the rough grading of her grammar. She told me that she is a journalism major/writer and no professor had ever taken points away from her for her grammar. I referred her to the College Writing Center.